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Amplitude Histogram-Based Method of Analysis of Patch Clamp Recordings that Involve Extreme Changes in Channel Activity Levels

  • Daniel Yakubovich
  • Ida Rishal
  • Carmen W. Dessauer
  • Nathan DascalEmail author
Article

Abstract

Many ion channels show low basal activity, which is increased hundreds-fold by the relevant gating factor. A classical example is the activation G-protein-activated K+ channels (GIRK) by Gβγ subunit dimer. The extent of activation (relative to basal current), R a, is an important physiological parameter, usually readily estimated from whole cell recordings. However, calculation of R a often becomes non-trivial in multi-channel patches because of extreme changes in activity upon activation, from a seemingly single-channel pattern to a macroscopic one. In such cases, calculation of the net current flowing through the channels in the patch, \(\overline I \), before and after activation may require different methods of analysis. To address this problem, we utilized neuronal GIRK channels activated by purified Gβγ in excised patches of Xenopus oocytes. Channels were expressed at varying densities, from a few to several hundreds per patch. We present a simple and fast method of calculating \(\overline I \) using amplitude histogram analysis and establish its accuracy by comparing with \(\overline I \) calculated from event lists. This method allows the analysis of extreme changes in \(\overline I \) in multichannel patches, which would be impossible using the standard methods of idealization and event list generation.

Keywords

Ion channel Kir3 Patch clamp G protein Amplitude histogram 

Notes

Acknowledgments

This work was supported by grants from NIH [GM68493 (N.D.) and GM60419 (C.W.D.)] and US–Israel Binational Science Foundation (01-122, N.D. and C.W.D). The authors report no conflicts of interest.

Supplementary material

12031_2008_9117_MOESM1_ESM.doc (25 kb)
ESM 1 (DOC 25.0 KB)

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Copyright information

© Humana Press 2008

Authors and Affiliations

  • Daniel Yakubovich
    • 1
  • Ida Rishal
    • 1
    • 3
  • Carmen W. Dessauer
    • 1
    • 2
  • Nathan Dascal
    • 1
    Email author
  1. 1.Department of Physiology and Pharmacology, Sackler School of MedicineTel Aviv UniversityTel AvivIsrael
  2. 2.Department of Integrative Biology and Pharmacology, Medical SchoolUniversity of TexasHoustonUSA
  3. 3.Weizmann Institute of ScienceRehovotIsrael

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